void switch_eg(long x, long n, long *dest) {
    long val = x;
    switch (n) {
    case 100:
        val *= 13;
        break;
    case 102:
        val += 10;
    case 103:
        val += 11;
        break;
    case 104:
    case 106:
        val *= val;
        break;
    default:
        val = 0;
    }
    *dest = val;
}

int main() {
    long *p;
    switch_eg(10, 20, p);
}